Updated db schema diagram
Enable eager trials for filter set feature test again
Refactor Context/vocabulary into own Vocabulary module
Extended vocabulary with build for context set and user
Admin interface: keyword list and tests thereof

Squashed commit of the following:

commit 308270f367e110c4985fd149abb0a7c4e806480f
Author: Michał Podlecki <m.podlecki@op.pl>
Date:   Mon Jun 9 13:26:28 2014 +0200

    Squashed commits:

    - Admin interface: keyword list
    - tests for keyword list